scholarly journals Basic Theory and Methods of Afforestation

Silviculture ◽  
2021 ◽  
Author(s):  
Jie Duan ◽  
Dilnur Abduwali
Keyword(s):  
Site Preparation ◽  
Site Classification ◽  
Forest Site ◽  
Site Conditions ◽  
Site Factors ◽  
Land Preparation ◽  
Forest Sites ◽  
Survival And Growth ◽  
Healthy Growth ◽  
The Right

Afforestation is an important practice in silviculture. This chapter outlines the forest site, site preparation, selection of afforestation materials in the process of afforestation. The life cycle of forests is very long, and it is difficult to change them once afforested. Therefore, the forest site must be analyzed in depth before afforestation to maintain the success of afforestation and the healthy growth of forests later. Forest sites are mainly affected by environmental and human activities. To facilitate afforestation, it is necessary to evaluate and classify the forest site factors and achieve a suitable species planted on the right site. Site preparation is also based on site classification. It is usually carried out after determining the type of afforestation land, divided into mechanical land preparation and chemical methods. An essential task of site preparation is to maintain soil moisture and promote seedlings’ survival and growth. Afforestation materials are mainly divided into three categories: seed, seedling, and cutting. The choice of these three types of afforestation materials and methods is related to site conditions, tree species, and age.

scholarly journals The demand of hybrid aspen (Populus tremula × P. tremuloides) on site conditions for a successful establishment on forest land

Silva Fennica ◽  
2018 ◽  
Vol 52 (5) ◽  
Author(s):  
Karin Hjelm ◽  
Lars Rytter
Keyword(s):  
Agricultural Land ◽  
Site Preparation ◽  
Populus Tremula ◽  
Deciduous Tree ◽  
Forest Site ◽  
Site Conditions ◽  
Hybrid Aspen ◽  
Forest Land ◽  
Preparation Methods ◽  
Patch Scarification

Hybrid aspen ( L. × Michx.) is a deciduous tree species suitable for producing large amounts of renewable biomass during short rotations. Its potential under North European conditions could be largely extended if not only agricultural land but also forest land was used for cultivation. Unfortunately, the knowledge of appropriate forest site conditions and effects of site preparation methods on hybrid aspen establishment is limited. In this paper, two studies that explore these questions are presented. In the first study, the sensitivity to acid soils was tested under greenhouse conditions in two type of soils: a) peat soil limed to certain pH levels (3.4–5.7) and b) collected forest soils where pH varied from 3.9 to 5.3. The lowest pH level resulted in reduced growth, elsewhere no significant differences were found. The second study was applied in the field and investigated the effect of four site preparation methods on survival and growth. The methods were: 1) control with no site preparation, 2) patch scarification, 3) mounding and 4) soil inversion. While no differences were found for survival, mounding was generally the method with the highest growth and patch scarification was least successful. The result was probably an effect of good soil aeration and less competition from vegetation after mounding. The field study also revealed clonal differences in growth performance, which stresses the importance of clone selection prior to planting. The results of these studies indicate that hybrid aspen is less sensitive to variation in pH and site preparation methods compared with other poplar species, as have been found in similar studies.Populus tremulaP. tremuloides

scholarly journals PERFORMANCE DA MODELAGEM PARA CLASSIFICAÇÃO DE SÍTIOS FLORESTAIS EM BASES DE DADOS COM OUTLIERS

Nativa ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 54-61
Author(s):  
Pábulo Diogo de Souza ◽  
Carlos Alberto Araújo Júnior ◽  
Christian Dias Cabacinha ◽  
Leandro Silva de Oliveira ◽  
Celso Dotta Lopes Junior ◽  
...  
Keyword(s):  
Radial Basis Function ◽  
Basis Function ◽  
Multilayer Perceptron ◽  
Forest Inventory ◽  
Eucalyptus Grandis ◽  
Site Index ◽  
Site Classification ◽  
Forest Site ◽  
Forest Sites ◽  
Forest Site Classification

As informações utilizadas para estimativa da capacidade produtiva de sítios florestais provêm de bases de dados de inventário florestal que podem conter observações discrepantes (outliers). Assim, torna-se necessário a análise de consistência para exclusão destes. Porém, os outliers podem representar determinado padrão de crescimento existente na floresta, logo a exclusão destes pode ser uma ação equivocada. Objetivou-se comparar a performance de diferentes técnicas de modelagem para classificação de sítios florestais, considerando uma base de dados com a presença de outliers. Utilizou-se pares de dados de idade e altura dominante (HD) de parcelas permanentes de Eucalyptus urophyla x Eucalyptus grandis localizadas no norte de Minas Gerais. Foi simulado um outlier de HD. A base de dados foi modelada, com e sem presença de outliers, por regressão linear (RL) e redes neurais artificiais Multilayer Perceptron (MLP) e Radial Basis Function (RBF). Os métodos foram analisados por meio dos critérios estatísticos de precisão: bias, raiz quadrada do erro médio, correlação de Pearson, erro médio percentual e gráfico de dispersão residual. A MLP foi superior para estimativa do índice de sítio. Portanto, a MLP é indicada para classificação de sítios florestais quando há presença de outliers na base de dados. Palavras-chave: índice de sítio; inventário florestal; dados discrepantes.   Performance of modeling for classification of forest sites in databases with outliers   ABSTRACT: The information used to estimate the productive capacity of forest sites comes from forest inventory databases that may contain discrepant observations (outliers). Thus, consistency analysis is required to exclude these. However, the outliers may represent a certain growth pattern existing in the forest, so their exclusion may be a mistaken action. The objective was to compare the performance of different modeling techniques for forest site classification, considering a database with the presence of outliers. We used pairs of data of age and dominant height (HD) of permanent parcels of Eucalyptus urophila x Eucalyptus grandis located in the north of Minas Gerais. A HD outlier was simulated. The database was modeled, with and without the presence of outliers, by linear regression (RL) and artificial neural networks Multilayer Perceptron (MLP) and Radial Basis Function (RBF). The methods were analyzed by means of precision statistical criteria: bias, square root of mean error, Pearson correlation, mean percentage error and residual scatter plot. The MLP was superior for site index estimation. Therefore, the MLP is indicated for forest site classification when there are outliers in the database. Keywords: site index; forest inventory; discrepant data.

scholarly journals Quelle est la place des champignons supérieurs dans les stations forestières? | What is the status of higher fungi in forest site classification?

2003 ◽  
Vol 154 (5) ◽  
pp. 149-160 ◽  
Author(s):  
François Ayer ◽  
Peter Lüscher ◽  
Simon Egli
Keyword(s):  
Mycorrhizal Fungi ◽  
Environmental Changes ◽  
Acid Soils ◽  
Fungal Species ◽  
Site Classification ◽  
Forest Site ◽  
Alkaline Soils ◽  
Forest Types ◽  
Data Set ◽  
Forest Sites

17 forest sites in three Swiss cantons (Berne, Solothurn, Fribourg)were investigated mycologically during a four year period to find out to what extent higher fungi are bound to specific forest sites and whether they are suitable for characterizing forest types. The species lists reveal a species specific dependency on soil pH: 32% of the inventorized fungal species can be found in the whole pH range, 50% were found only in acid soils up to a pH of 5.75, and 18% in only neutral to alkaline soils. The species fructifying on slightly acid to neutral soils are considered to be possible indicator species for such environmental changes as acidification or eutrophisation. The present classification of higher fungi into pH-classes and forest types is a tentative one. The data set will be supplemented with further observations in order to attain a more definitive classification. These preliminary analyses, however, already reveal the suitability of higher fungi for characterizing and classifying forest types. The four-year investigation showed that pure coniferous forests are richer in macromycetes species than generally supposed and also that they harbour a higher percentage of mycorrhizal fungi than deciduous forests.

The current status of forest site classification in Ontario

1992 ◽  
Vol 68 (1) ◽  
pp. 64-77 ◽  
Author(s):  
R. A. Sims ◽  
P. Uhlig
Keyword(s):  
Resource Management ◽  
Building Blocks ◽  
Current Status ◽  
Background Information ◽  
Site Classification ◽  
Land Resource ◽  
Forest Site ◽  
Forest Sites ◽  
Soil Site ◽  
Forest Site Classification

Forest sites are diagnostic forest-landscape ecosystem units that resource managers must deal with during the planning and implementation stages of management. Forest sites are the basic building blocks for undertaking integrated resource management which weighs wildlife, recreation, environmental impact and various other concerns along with timber harvesting. Consequently, accurate and practical systems for classifying and mapping forest sites are becoming increasingly necessary to organize, communicate and use existing and new management knowledge and experience effectively.Over the past four decades in Ontario, a number of studies and resource surveys have provided important background information on forest sites. Many have considered, to varying extents, the integrative roles of vegetation, soil-site, landform and general climate on forests and forest land. Generally, the emphasis has been on description and classification, with results generating a better understanding of how various forests in different areas develop, both qualitatively and quantitatively, in relation to soil-site or other features of the basic land resource. Some of these studies and surveys have been instrumental in advancing the definitions and understanding of forested ecosystems. Others have provided new information on site dynamics, interrelationships and functions, or have contributed to the science (and art) of site evaluation and classification.This paper briefly summarizes the current status of forest site classification in Ontario. Over time, the role of forest site classification has evolved in response to new technologies and information, and to new emphases and values in resource management. In general, site classification research has become increasingly integrative and quantitative. Some of the important future challenges facing forest site classification in Ontario are briefly discussed. Key words: ecological land classification, forest ecology, forest ecosystem classification, forest management interpretations, forest site classification, land use planning, Ontario.

scholarly journals Comparative analysis of natural and artificial regeneration in Nowa Dęba Forest District

2019 ◽  
Vol 61 (3) ◽  
pp. 230-241
Author(s):  
Justyna Długosiewicz ◽  
Stanisław Zając ◽  
Emilia Wysocka-Fijorek ◽  
Małgorzata Sułkowska
Keyword(s):  
Scots Pine ◽  
Coniferous Forest ◽  
Forest Site ◽  
Site Conditions ◽  
Artificial Regeneration ◽  
Forest Sites ◽  
Pine Regeneration ◽  
Pine Stands ◽  
Forest District ◽  
Scots Pine Stands

Abstract New challenges related to the multifunctional role of forests in consideration of both natural environment and economy come into view sequentially. In current forestry practice, an important element is not only the quality of forest cultivations (silvicultural aspect) but also the costs incurred for their production and tending (economic aspect). The main purpose of this article is to show the prospect of increasing positive silvicultural effects depending on the method used in management of Scots pine stands under given site conditions. The comparative analysis was carried out using the study results obtained in the Forest District Nowa Dęba and those presented in other relevant studies. In the present study, we examined whether the site conditions have significant effects on silvicultural and economic effectiveness of regeneration and development of Scots pine stands or those predominated by Scots pine in the initial stages of stand growth. Significance of the regeneration method effects on growth characteristics of Scots pine regeneration as well as the costs of forest cultivation management was analysed. The study on silvicultural and economic effectiveness was carried out in the Forest District Nowa Dęba. The results obtained showed that using Scots pine natural regeneration under the conditions of fresh coniferous forest site and fresh mixed coniferous forest site was the way of management based on reason. This was supported by both the values of regeneration growth parameters and silvicultural quality along with clearly lower expenditures incurred to achieve these effects. In wet mixed coniferous site, Scots pine seedlings regenerated naturally; however, the results indicated their lower silvicultural quality and growth parameter values when compared to those artificially regenerated. In fresh mixed broadleaved forest site, equally for silvicultural and economic reasons, the more optimal option was to regenerate forest using traditional planting material as natural Scots pine regeneration showed lower silvicultural effects. The unit costs of regeneration and maintenance of stands with self-sown Scots pine in fresh mixed broadleaved forest site were higher when compared with other examined forest sites. On the basis of the results of the present study, it can be concluded that regardless of the regeneration method examined, the most differentiating factor of the final economic effect of Scots pine stand establishment and maintenance was the cost of regeneration operation. The expenditure for this purpose consumed the largest part of expenses incurred in artificial regeneration variant. The higher cost of corrections in artificially planted forest cultivations in poorer forest sites was one of the reasons behind the profitable final balance of naturally regenerating Scots pine stands. Differences between other costs analysed were not significant. The results of the present study may contribute to comprehensive assessments of natural and artificial ways of forest regeneration and indicate forest production costs that are the most closely related to site conditions.

Influence of Site Preparation on Soil Conditions Affecting Stand Establishment and Tree Growth

1988 ◽  
Vol 12 (3) ◽  
pp. 170-178 ◽  
Author(s):  
Lawrence A. Morris ◽  
Robert F. Lowery
Keyword(s):  
Soil Properties ◽  
Tree Growth ◽  
Site Preparation ◽  
Soil Conditions ◽  
Forest Site ◽  
Stand Establishment ◽  
Positive Effects ◽  
Survival And Growth ◽  
Induced Changes ◽  
Changes In Soil Properties

Abstract Slash disposal, and the type and amount of competing vegetation that occur on a forest site, are the primary considerations of site preparation prescriptions. Site preparation effectiveness, as measured by pine survival and growth, can be improved by recognizing and separating soil manipulation effects from those that result from competition control. The data relating site preparation induced changes in soil properties to plantation growth are limited, but indicate that many common treatments have little potential for improving soil conditions. Only disking, bedding, and subsoiling are likely to have large positive effects. South. J. Appl. For. 12(3):170-178.

scholarly journals EVAPORATION PATTERNS IN FORESTS OF DIFFERENT AGES, SITE CONDITIONS, AND PRODUCTIVITY LEVELS

2020 ◽  
pp. 49-67
Author(s):  
Yu.V. Karpechko ◽  
S.A. Kondratyev ◽  
V.Z. Rodionov ◽  
M.V. Shmakova
Keyword(s):  
Forest Type ◽  
Southern Taiga ◽  
Limiting Factor ◽  
Radiation Balance ◽  
Total Biomass ◽  
Forest Site ◽  
Site Conditions ◽  
Quality Class ◽  
Age Related ◽  
Forest Sites

The paper analyzes the factors behind evaporation from a forest: foliage and solar irradiance. The patterns of foliage formation and its changes with age in forests of varying productivity are demonstrated. The limiting factor for stand growth and development in each type of forest is the energy resources available. The average radiation balance of a region being given, the stand productivity depends on the characteristics of the locality, which influence soil fertility and predetermine the forest type. The southwards enhancement of the quality class of a forest type with a rise in the radiation balance is associated with the growing share of foliage and intensification of biochemical processes. The share of foliage mass in the total biomass of the tree stand depends on the forest site conditions, quality class, and energy supply. Previously designed techniques have been applied to calculate age-related patterns of evaporation from forest sites of varying habitat conditions and productivity in middle and southern taiga. As the radiation balance grows, physical evaporation from forest areas increases, and the growing share of foliage in the tree stand’s total biomass enlarges transpiration by the stand in every forest type and quality class. Alteration of site conditions entails a change in the age-related pattern of evaporation and transpiration by the stand. Enhancement of site conditions and quality characteristics leads to an increase in evaporation in young and middle-aged forests, however in mature and over-mature forests this trend may be broken. The greatest evaporation and transpiration by the stand are observed at an age when current biomass increment is the highest and the amount of foliage is at maximum. According to our calculations, the age of maximum annual total evaporation and transpiration varies from 50 to 100 years depending on the forest site conditions

scholarly journals The composition and diversity of natural regeneration of tree species in gaps under different intensities of forest disturbance

2021 ◽  
Author(s):  
Maame Esi Hammond ◽  
Radek Pokorný ◽  
Daniel Okae-Anti ◽  
Augustine Gyedu ◽  
Irene Otwuwa Obeng
Keyword(s):  
Tree Species ◽  
Natural Regeneration ◽  
Forest Disturbance ◽  
Forest Site ◽  
Gap Formation ◽  
Tree Species Composition ◽  
Forest Sites ◽  
Significant Difference ◽  
Shade Tolerant Species ◽  
Disturbed Forest

AbstractThe positive ecological interaction between gap formation and natural regeneration has been examined but little research has been carried out on the effects of gaps on natural regeneration in forests under different intensities of disturbance. This study evaluates the composition, diversity, regeneration density and abundance of natural regeneration of tree species in gaps in undisturbed, intermittently disturbed, and disturbed forest sites. Bia Tano Forest Reserve in Ghana was the study area and three gaps each were selected in the three forest site categories. Ten circular subsampling areas of 1 m2 were delineated at 2 m spacing along north, south, east, and west transects within individual gaps. Data on natural regeneration < 350 cm height were gathered. The results show that the intensity of disturbance was disproportional to gap size. Species diversity differed significantly between undisturbed and disturbed sites and, also between intermittently disturbed and disturbed sites for Simpson’s (1-D), Equitability (J), and Berger–Parker (B–P) indices. However, there was no significant difference among forest sites for Shannon diversity (H) and Margalef richness (MI) indices. Tree species composition on the sites differed. Regeneration density on the disturbed site was significantly higher than on the two other sites. Greater abundance and density of shade-dependent species on all sites identified them as opportunistic replacements of gap-dependent pioneers. Pioneer species giving way to shade tolerant species is a natural process, thus make them worst variant in gap regeneration.

scholarly journals Four Site-Preparation Techniques for Regenerating Pine-Hardwood Mixtures in the Piedmont

1997 ◽  
Vol 21 (3) ◽  
pp. 116-122 ◽  
Author(s):  
Thomas A. Waldrop
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Height Growth ◽  
Site Preparation ◽  
Site Conditions ◽  
Growing Seasons ◽  
Southern Appalachian ◽  
Medium Quality ◽  
Pinus Taeda L ◽  
Preparation Techniques

Abstract Four variations of the fell-and-burn technique, a system developed to produce mixed pine-hardwood stands in the Southern Appalachian Mountains, were compared in the Piedmont region. All variations of this technique successfully improved the commercial value of low-quality hardwood stands by introducing a pine component. After six growing seasons, loblolly pine (Pinus taeda L.) occupied the dominant crown position and oaks the codominant position in fell-and-burn treated stands on poor to medium quality sites. The precise timing of felling residual stems, as prescribed by the fell-and-burn technique, may be flexible because winter and spring felling produced similar results. Although summer site preparation burns reduced hardwood height growth by reducing the length of the first growing season, they did not improve pine survival or growth. Pines were as tall as hardwoods within four growing seasons in burned plots and within six growing seasons in unburned plots. Additional research is needed to determine the level or intensity of site preparation needed to establish pine-hardwood mixtures over a range of site conditions. South. J. Appl. For. 21(3):116-122.

Evaluation of Snow Albedo in Land Models for Weather and Climate Studies

2010 ◽  
Vol 49 (3) ◽  
pp. 363-380 ◽  
Author(s):  
Zhuo Wang ◽  
Xubin Zeng
Keyword(s):  
Climate Models ◽  
Snow Water Equivalent ◽  
Weather Forecasting ◽  
Vegetation Type ◽  
Global Model ◽  
Forest Site ◽  
Snow Albedo ◽  
Community Land Model ◽  
In Situ Data ◽  
Forest Sites

Abstract Snow albedo plays an important role in land models for weather, climate, and hydrometeorological studies, but its treatment in various land models still contains significant deficiencies. Complementary to previous studies that evaluated the snow albedo as part of an overall land model study, the snow albedo formulations as used in four major weather forecasting and climate models [European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers for Environmental Prediction (NCEP) “Noah” land model, National Center for Atmospheric Research (NCAR) Community Land Model (CLM3), and NCEP global model] were directly evaluated here using multiyear Boreal Ecosystem–Atmosphere Study (BOREAS) in situ data over grass and forest sites. First, four idealized cases over grass and forest sites were designed to understand better the different albedo formulations in these models. Then the BOREAS data were used to evaluate snow albedo and relevant formulations and to identify deficiencies of each model. Based on these analyses, suggestions that involve only minor changes in parameters or formulations were made to significantly reduce these deficiencies of each model. For the ECMWF land model, using the square root of snow water equivalent (SWE), rather than SWE itself, in the computation of snow fraction would significantly reduce the underestimation of albedo over grass. For the NCEP Noah land model, reducing (increasing) the critical SWE for full snow cover over short (tall) vegetation would reduce the underestimate (overestimate) of snow albedo over the grass (forest) site. For the NCAR CLM3, revising the coefficient used in the ground snow-fraction computation would substantially reduce the albedo underestimation over grass. For the albedo formulations in the NCEP global model, replacing the globally constant fresh snow albedo by the vegetation-type-dependent Moderate-Resolution Imaging Spectroradiometer (MODIS) maximum snow albedo would significantly improve the overestimation of model albedo over forest.

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